The present invention relates generally to a speaker for an automotive vehicle audio system, adapted to produce audio sound, particularly relatively low-frequency sounds. More specifically, the invention relates to a speaker using a vehicle panel as a replacement for the speaker cone of a cone-type speaker.
Generally, speakers for an automotive vehicle audio system are provided at various locations in the vehicle compartment. Conventionally, cone-type speakers are used for the vehicle audio system for producing audio sound in a frequency range suitable for clearly reproducing audio sound. However, since space in the vehicle compartment available for the speakers is seriously limited, the size of the cone-type speakers to be facilitated in the vehicle compartment must be limited. On the other hand, for clearly producing substantially low-frequency sounds such as sounds at frequencies less than 500 Hz, the speaker diameter must be approximately 20 cm. Such a large speaker cannot be installed in the vehicle compartment without significantly reducing the space in the vehicle compartment. Particularly, in an audio system having recessed speakers disposed between inner and outer vehicle panels or installed below the rear parcel shelf, the size of the speaker which can be used is strictly limited.
Consequently, for the standard passenger car, a 5-to-10-cm-diameter speaker is used. This degrades the audio sound quality being produced, particularly with respect to relatively low-frequency sounds.